CYTOGENETIC ANALYSIS OF HUMAN OOCYTES PARTHENOGENETICALLY ACTIVATED BY PUROMYCIN

Purpose: Treatment of aged human oocytes by puromycin allows a high ra te of parthenogenetic activation and development until the first cleav age division. This technique was used for the study of the chromosome complement of oocytes which remained unfertilized after in vitro ferti lization. Three hundred four infertilized oocytes were treated with 10 mu g/ml puromycin for 6-8 hr and further cultured for 12-15 hr. Resul ts: Activation occurred in 90.5% of the oocytes. Heterozygous diploids with two pronuclei predominated (61%), which is in contrast to the mo use, where rite majority of oocytes activated by puromycin ar uniform haploids (89%). Conclusions: Therefore we conclude that puromycin trea tment induces retention of the second polar body in human oocytes, unl ike in mouse oocytes treated in the same way. Chromosome analysis perf ormed on 182 oocytes suggested a nondisjunction (ND) rate for the seco nd meiotic division of 12.7%. This is a low figure considering the fac t that puromycin itself has been reported to induce nondisjunction. Fo r the first meiotic division a ND rate of only 5.6% was found. This ra te is lower than the one found in metaphase II arrested oocytes and Iv e believe that this difference is due to the technical differences bet ween the study of meiotic and that of mitotic chromosomes.